1. Field of the Invention
The present invention relates to a method of manufacturing a thin-film magnetic head, a thin-film magnetic head manufacturing apparatus, and a thin-film magnetic head manufacturing system that manufacture a thin-film magnetic head by carrying out an etching process on an object to be worked to work a part to be worked of the object to be worked to a target length.
2. Description of the Related Art
As one example of this type of method of manufacturing a thin-film magnetic head, in Japanese Laid-Open Patent Publication No. 2000-105906 the present applicant discloses a method of manufacturing a composite thin-film magnetic head including an inductive write element and an MR read element. When manufacturing a thin-film magnetic head according to this method, thin films such as a first magnetic film, a gap film, a coil film, and a coil insulating film are first laminated onto a base according to a well-known process to form a multilayer structure. Next, a photoresist is applied onto the multilayer structure and is patterned to form a resist frame. After this, electroplating or the like is carried out to form a second magnetic film inside a region surrounded by the resist frame. By doing so, a second pole portion is formed on the first magnetic film with the gap film in between. At this stage, the track width of the second pole portion that has been formed is equal to the size of a gap that is provided in the resist frame described above at the formation position of the second pole portion when the resist frame described above was formed.
Since it is difficult to form an extremely narrow gap at the formation position of the second pole portion by photolithography during the formation of the resist frame, it is extremely difficult to form a second pole portion with a sufficiently narrow track width by electroplating using a resist frame. Accordingly, to stabilize the magnetic characteristics and to improve the recording performance, the applicant has started reducing the track width of (i.e., narrowing) the second pole portion using the following method. More specifically, after the resist frame has been removed from the multilayer structure, a dry etching process is carried out on the second pole portion for a predetermined processing time. By doing so, it is possible to reduce the track width of the second pole portion to 1.0 μm or below (for example, around 0.8 μm). After this, by forming a protective film and the like by a well-known process so as to cover the second pole portion and the like, the thin-film magnetic head is completed.
In this way, when dry etching is carried out to narrow a second pole portion that has been formed by electroplating using a resist frame, as one example, the processing time of the dry etching required to reduce the second pole portion to the desired track width is set based on information obtained during a manufacturing process that produced samples or during a manufacturing process for products carried out before the present process. More specifically, the track width of the second pole portion formed by electroplating (hereinafter referred to as the “length before working”), the track width of the second pole portion that has been narrowed by dry etching (hereinafter, referred to as the “length after working”), and the processing time of the dry etching process are obtained and the etching rate during the etching process on the second pole portion (the second magnetic film) is calculated based on such information. During the manufacturing of a product, the length before working of a second pole portion formed by electroplating is measured and the processing time required to work the second pole portion to the target length is calculated based on the etching rate obtained in advance. By doing so, a second pole portion with the desired length (the target length) is formed by carrying out the dry etching process for the calculated processing time.